Method for repairing at least one defective individual cell of a battery module

Abstract

The invention relates to a method for replacing at least one defective individual cell (1) of a battery module of an electrical energy storage device with several permanently connected individual cells (1), wherein each individual cell (1) comprises an electrochemically active unit (2), a cell housing (3) for receiving the electrochemically active unit (2), and at least one electrical conductor (1.1) for electrically connecting the individual cell (1). According to the invention, in the case of an individual cell (1) with a defective electrochemically active unit (2), at least one connected electrical conductor (1.1) of the unit is disconnected, the cell housing (3) is opened, the defective electrochemically active unit (2) is removed, a new insert cell (4) is inserted into the opened cell housing (3), and at least one electrical conductor (4.1) of the insert cell (4) is electrically connected.

Description

[0001] The invention relates to a method for replacing at least one defective individual cell of a battery module of an electrical energy storage device with a plurality of individual cells firmly connected to one another, wherein the respective individual cell comprises an electrochemically active unit, a cell housing for receiving the electrochemically active unit and at least one electrical conductor for electrically connecting the individual cell.

[0002] DE 10 2014 016 025 A1 discloses a method and a device for replacing a defective individual cell in an electric battery module of an electric battery. The individual cells are connected to a thermally conductive carrier body at their ends in a form-fitting and material-locking manner, and the material-locking connection between the individual cells and the carrier body is created by a potting compound arranged in a space between the carrier body and the individual cells, as well as in a space between the individual cells in the region of the carrier body. In one method step, a separating element comprising a hollow cylindrical body and cutting teeth arranged on the end face of the hollow cylindrical body is placed onto the defective individual cell.In a further process step, the material connection between the defective individual cell and the carrier body is released, and in a further process step, the released, defective individual cell is removed from the electrical battery module.

[0003] Furthermore, DE 10 2013 010 313 A1 describes a device and a method for replacing an individual cell of an electric battery module of an electric battery comprising a plurality of electrically interconnected individual cells. Each individual cell is arranged within a frame formed from two frame elements, wherein a first cell conductor tab of the respective individual cell is materially connected to a cell connector of a first frame element in a connecting region, and a second cell conductor tab is materially connected to a cell connector of a second frame element. The battery module is fastened by means of a fastening structure in a force-fitting, material-fitting, and form-fitting manner to a support structure for receiving the battery module, and to disassemble the individual cell, two directly adjacent frame elements of the battery module are spaced apart from one another by moving two partial regions of the fastening structure.In addition, the material connection of the respective cell conductor tab is separated from the corresponding cell connector using several tools and the cell connector is mechanically reworked in the connection area after the separation.

[0004] Furthermore, DE 10 2013 010 314 A1 and JP2012069332 each disclose a method for replacing a single cell of an electric battery.

[0005] The invention is based on the object of providing a novel method for replacing a defective individual cell of a battery module of an electrical energy storage device.

[0006] The object is achieved according to the invention by a method which has the features specified in claim 1.

[0007] Advantageous embodiments of the invention are the subject of the subclaims.

[0008] A method for replacing at least one defective individual cell of a battery module of an electrical energy storage device with a plurality of individual cells firmly connected to one another, wherein the respective individual cell comprises an electrochemically active unit, a cell housing for receiving the electrochemically active unit and at least one electrical conductor for electrically connecting the individual cell, provides according to the invention that in the case of an individual cell with a defective electrochemically active unit - at least one of whose connected electrical arresters is disconnected, - the cell casing is opened, - the defective electrochemically active unit is removed, - a new single cell insert, in particular one with dimensions corresponding to the cell housing, is inserted into the opened cell housing and - at least one electrical arrester of the single cell is electrically connected.

[0009] By applying the method, it is possible to replace a defective single cell, in particular a single cell with a defective electrochemically active unit, with a replacement single cell, also called a repair cell, with a functional electrochemically active unit in a comparatively cost-efficient and resource-saving manner.

[0010] Because the insert single cell is inserted into the already existing and firmly connected cell housing of the defective single cell, it is not necessary to replace the entire battery module, but only the electrochemically active unit, for example in the form of an electrode foil stack or an electrode foil wrap, with the insert single cell.

[0011] In one embodiment, the cell housing is opened in the region of an edge of a cell housing cover such that the defective electrochemically active unit can be completely removed. The cell housing is thus opened such that the resulting opening is / is selected to be sufficiently large to remove the defective electrochemically active unit from the cell housing, for example, completely.

[0012] In one possible embodiment, the cell housing cover is separated from the cell housing of the defective single cell by cutting, leaving the permanently installed cup-shaped cell housing in the battery module, into which the insert single cell is inserted. The cell housing thus forms a receiving unit for the insert single cell.

[0013] In another embodiment, a predetermined amount of adhesive is applied to the cell housing before inserting the insert cell into the cell housing. After the insert cell is inserted, the adhesive creates a bond between the insert cell and the cell housing of the defective single cell remaining in the battery module. This securely fixes the insert cell in the cell housing present in the battery module.

[0014] In one embodiment, a predetermined amount of an adhesive can be selected such that after inserting the single insert cell into the cell housing, the single insert cell is / is enclosed with adhesive at least in a lower region / bottom region, in a jacket region of the single insert cell.

[0015] In one embodiment, a predetermined amount of adhesive is introduced into the cell housing such that, when the single-cell insert is inserted into the cell housing, the adhesive completely fills the gap between the cell housing and the single-cell insert. This means that essentially all cavities between the cell housing and the single-cell insert are filled, and the single-cell insert is fixed in its position within the cell housing.

[0016] In one possible embodiment, the adhesive is used to dissipate heat generated during operation of the replacement single cell to the outside via the adhesive and the cell housing, whereby the fact that the cavities are filled optimizes heat conduction between the insert single cell, the cell housing and the environment, and the heat generated during operation of the replacement single cell, in particular during charging and discharging, is efficiently dissipated, for example in the direction of a temperature control device.

[0017] In one embodiment, a thermally conductive adhesive is applied to the cell housing as an adhesive, allowing efficient and optimized heat dissipation from the individual cell insert, for example, toward the temperature control device. By using a thermally conductive adhesive as the adhesive, heat dissipation is optimized, thus largely counteracting overheating of the individual cell insert.

[0018] In one version, the defective individual cell is deeply discharged after the electrical arrester has been disconnected and cooled using dry ice, so that heat development and any resulting fire can be counteracted as far as possible.

[0019] Embodiments of the invention are explained in more detail below with reference to drawings.

[0020] Showing: Fig. 1A schematically shows a sectional view of a single cell with a defective electrochemically active unit, Fig. 1B schematically shows a sectional view of an opened cell housing of the single cell, Fig. 1C schematically shows a sectional view of the cell housing without the defective electrochemically active unit, Fig. 1D schematically shows a sectional view of the cell housing during insertion of a single insert cell and Fig. 1E schematically shows a sectional view of the cell housing with the fully inserted single cell.

[0021] Corresponding parts are provided with the same reference numerals in all figures.

[0022] The Fig. 1A to 1E show a sequence of replacing a defective individual cell 1 of a battery module (not shown in detail) of an electrical energy storage device for a vehicle, in particular an electric vehicle, a hybrid vehicle or a vehicle powered by fuel cells.

[0023] Fig. Figure 1A shows a sectional view of a single cell 1 with a defective electrochemically active unit 2, wherein Fig. 1B a sectional view of an opened cell housing 3 of the single cell 1 and in Fig. 1C shows a sectional view of the cell housing 3 without the defective electrochemically active unit 2. Fig. 1D shows a sectional view of the cell housing 3 during insertion of a single insert cell 4 and in Fig. 1E shows a sectional view of the cell housing 3 with the fully inserted single cell 4.

[0024] Such a single cell 1 is a so-called round cell, which has a cell housing 3 in which an electrochemically active unit 2, in particular an electrode foil coil, is arranged and the cell housing 3 is tightly closed by means of a cell housing cover 3.1.

[0025] An electrical energy storage device typically comprises several such battery modules, each battery module having several individual cells 1 permanently connected to one another. Each individual cell 1 has at least one electrical conductor 1.1, in particular in the form of an electrical pole, wherein the electrical conductors 1.1 are connected to one another for the electrical interconnection of adjacently arranged individual cells 1.

[0026] If it is determined, for example based on an electrical voltage monitoring of the battery module, that an individual cell 1, in particular its electrochemically active unit 2, is defective, the battery module is usually replaced or the defective individual cell 1 is electrically bridged.

[0027] If a battery module replacement is planned for a defective individual cell 1, this is associated with comparatively high costs. However, a prerequisite for a battery module replacement is that the electrical energy storage device is designed for this purpose. If the electrical energy storage device is designed for this purpose, this can have a negative impact on the volumetric energy of the electrical energy storage device.

[0028] If, however, it is intended to electrically bridge the defective individual cell 1, the electrical behavior of the electrical energy storage device may be negatively influenced.

[0029] In the following, a method for replacing a defective single cell 1 arranged in a battery module and firmly connected to a plurality of single cells 1 is described, wherein the method represents a cost-effective and resource-saving solution.

[0030] If a defective single cell 1 is detected in the battery module, a connection of the electrical arrester 1.1 of the defective single cell 1 is disconnected. Subsequently, as in Fig. 1A, the cell housing cover 3.1 is separated from the cell housing 3, in particular by means of a cutting tool 5. This means that the individual cell 1 is opened at its cell housing cover 3.1 using a suitable tool. In one embodiment, the cell housing 3 is opened at an edge surrounding the cell housing cover 3.1.

[0031] If the cell housing cover 3.1 is separated from the cell housing 3, the cell housing 3 has a sufficiently large opening to completely remove the electrochemically active unit 2 from the cell housing 3 and dispose of it, as symbolized by a garbage can 6. Once the electrochemically active unit 2 is removed from the cell housing 3, only the cup-shaped cell housing 3 remains. For example, the cell housing cover 3.1 can be disposed of like the electrochemically active unit 2.

[0032] In the cell housing 3, as shown in Fig. 1C, an adhesive K, in particular a thermally conductive adhesive, is introduced in a predetermined amount. In particular, the adhesive K is placed centrally on a bottom region of the cell housing 3 and introduced into the latter.

[0033] An insert single cell 4 is then inserted into the cell housing 3, which is firmly connected to the adjacent single cells 1 of the battery module, as shown in Fig. 1D. For this purpose, the insert single cell 4 has suitable electrical properties and dimensions that correspond to the dimensions of the cell housing 3. This means that the insert single cell 4 has a slightly smaller diameter than the cell housing 3. An outer diameter of an insert single cell 4 can be smaller than an inner diameter of a cell housing 3.

[0034] If the insert single cell 4 is inserted into the cell housing 3 and pressed toward the bottom area of ​​the cell housing 3, the adhesive K is distributed in the spaces between the insert single cell 4 and the cell housing 3 into which the insert single cell 4 is inserted. The adhesive K is distributed in the spaces in such a way that all cavities are largely filled with the adhesive K.

[0035] After a predetermined curing time of the adhesive K, the insert single cell 4 is positively and materially connected to the cell housing 3 of the previously defective single cell 1.

[0036] To commission the single-cell insert 4, its electrical arrester 4.1 is connected to an electrical arrester 1.1 of a neighboring single cell 1 of the battery module. Furthermore, another arrester of the single-cell insert 4 is also connected to a corresponding arrester of a neighboring single cell 1.

[0037] The features and advantages described herein with respect to a method for replacing at least one defective single cell may also relate to a single cell described herein and vice versa. List of reference symbols 1 single cell 1.1 electrical arrester 2 electrochemically active unit 3 cell housings 3.1 Cell housing cover 4 single cell deployments 4.1 electrical arrester 5 Cutting tool 6 garbage cans K Adhesive QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2014 016 025 A1

[0002] DE 10 2013 010 313 A1

[0003] DE 10 2013 010 314 A1

[0004] JP 2012069332

[0004]

Claims

[1] Method for replacing at least one defective individual cell (1) of a battery module of an electrical energy storage device with a plurality of individual cells (1) firmly connected to one another, wherein the respective individual cell (1) comprises an electrochemically active unit (2), a cell housing (3) for receiving the electrochemically active unit (2) and at least one electrical conductor (1.1) for electrically connecting the individual cell (1), characterized by that in a single cell (1) with a defective electrochemically active unit (2) - at least one of whose connected electrical arresters (1.1) is disconnected, - the cell housing (3) is opened, - the defective electrochemically active unit (2) is removed, - a new single cell (4) is inserted into the opened cell housing (3) and - at least one electrical conductor (4.1) of the single cell insert (4) is electrically connected. [2] Method according to claim 1, characterized by that the cell housing (3) is opened in the region of an edge of a cell housing cover (3.1) of the cell housing (3) in such a way that the defective electrochemically active unit (2) can be completely removed. [3] Method according to claim 2, characterized by that the cell housing cover (3.1) is separated from the cell housing (3) of the defective individual cell (1) by means of a cutting tool (5). [4] Method according to one of the preceding claims, characterized by that before inserting the single insert cell (4) into the cell housing (3), a predetermined amount of an adhesive (K) is introduced into the cell housing (3). [5] Method according to claim 4, characterized bythat the thus predetermined amount of the adhesive (K) is introduced into the cell housing (3) so that by means of the adhesive (K) when the insert single cell (4) is inserted into the cell housing (3) a space between the cell housing (3) and the insert single cell (4) is completely filled. [6] Method according to claim 4 or 5, characterized by that a thermally conductive adhesive is introduced into the cell housing (3) as adhesive (K). [7] Method according to one of the preceding claims, characterized by that the defective individual cell (1) is deeply discharged after separation of the electrical arrester (1.1) and cooled by means of dry ice.

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